1. Field of the Invention
The present invention relates to the DNA sequences encoding a pathogenesis related-10 (CbPR-10) protein from Capsicum baccatum. The gDNA contains a novel nucleic acid sequence for a promoter. The polypeptide of CbPR-10 shows weak ribo-nuclease activity, which becomes stronger after fungal induced phosphorylation of the protein. The invention also relates to the sequences comprising the cDNA sequence fused with invented or other appropriate promoter and terminator in a genetic construct for transformation of plants or industrial use. Such an expression of the genetic construct in plant results in an increased resistance to phytopathogenic fungi, especially anthracnose fungus.
2. Description of Prior Art
Plants respond to the invasion of phyto-pathogens by coordinated and integrated set of metabolic alterations. To resist the pathogen, various genes are induced at the infection site and distal part of the plant in association with the development of hypersensitive reaction (HR) and systemic acquired resistance (SAR), respectively. These genes include pathogenesis-related (PR) and antibiotic proteins, etc.
The PR proteins are a class of proteins that are synthesized in plants in response to pathogenic infection. Usually, PR proteins are not present in healthy plants, but are synthesized in response to pathological or related stresses. In the latest proposition, PR proteins are divided into 14 families based on their sequences, serological properties, and biological activities. When most PRs are extra-cellular proteins, PR-10 is the first described intracellular protein in cultured parsley cell upon elicitor treatment. It has been supposed that the intracellular PR-10 is capable of cleaving viral RNA or other pathogen's RNA in the plant cells. According to Park et al., (2004), CaPR-10 protein, isolated from Capsicum annuum, is phosphorylated upon TMV-P0 inoculation and functions as a kind of RNase being able to cleave viral RNA. Also, recombinant CaPR-10 inhibited oomycete growth as well as viral infection. So, it has been suggested that cytosolic phosphorylated PR-10 protein is an active component of an inducible-defense mechanism against pathogen infection.
A majority of cultivated pepper lines have been developed from C. annuum species which are very susceptible to anthracnose fungus. A pathogenic agent of anthracnose disease, Colletotrichum acutatum, causes the most destructive disease in widely cultivated pepper varieties and results in serious economical loss. By anthracnose fungus, most serious damage occurs in the fruit of pepper. This pathogen becomes necrotrophic after penetration into the epidermal cells, so that fungal hyphae colonize intracellularly in subcuticular tissues of the fruit. Since PR-10 localizes in the cytoplasm of the plant cell, it will be valuable to examine the inhibitory effect of PR-10 protein during the fungal infection. So, we isolated and characterized a PR-10 gene from C. baccatum that showed incompatible interaction with anthracnose fungus. Also, relative ribonuclease and antifungal activity were compared with previously reported CaPR-10 protein of the susceptible species, C. annuum. 
There are a few Capsicum accessions, such as C. baccatum and C. chinense species, showing resistance to anthracnose fungus. If defense related genes of resistant species are available, it will provide opportunities to transfer the genes into susceptible species. Recently, genetic engineering techniques are offering relief from the destructive disease in cultivated pepper lines through the development of fungus control systems using resistance related genes isolated from fungal resistant species. Ultimately, biotechnological applications of CbPR-10 protein may provide agronomically relevant level of disease control on pepper cultivation without harmful side effects.